Solve for $x$ : $10\sqrt{x} - 9 = 3\sqrt{x} + 6$
Explanation: Subtract $3\sqrt{x}$ from both sides: $(10\sqrt{x} - 9) - 3\sqrt{x} = (3\sqrt{x} + 6) - 3\sqrt{x}$ $7\sqrt{x} - 9 = 6$ Add $9$ to both sides: $(7\sqrt{x} - 9) + 9 = 6 + 9$ $7\sqrt{x} = 15$ Divide both sides by $7$ $\frac{7\sqrt{x}}{7} = \frac{15}{7}$ Simplify. $\sqrt{x} = \dfrac{15}{7}$ Square both sides. $\sqrt{x} \cdot \sqrt{x} = \dfrac{15}{7} \cdot \dfrac{15}{7}$ $x = \dfrac{225}{49}$